This document specifies the procedures to test implementations
\nof VMR-WB-compatible variable-rate speech codecs either by
\nmeeting the bit-exact implementation, or meeting recommended
\nminimum performance requirements<\/i>. This speech codec is
\ncorresponds to the Service Option 62 described in TIA-1016 [1]. The
\nVMR-WB codec corresponds to Service Option 62 and is used to
\ndigitally encode the speech signal for transmission at variable
\ndata rates of 13300, 6200, 2700, or 1000 bps. Like some other
\nspeech coding standards, this standard provides a bit-exact method
\nof testing the codec for minimum performance. In this optional
\nprocedure, a given set of test vectors are input to the test codec,
\nand the output vectors from the test codec must be bit-exact with
\nthe output vectors generated from the Software Distribution which
\nis part of this standard. If they are bit-exact, and the test codec
\ncomplies with Section 2.1.2, the codec passes the minimum
\nperformance requirement and no further testing is required. The
\nbit-exact mode of testing, however, is only applicable to codecs
\nwhose design conforms in all respects to the algorithmic
\ndescription of the VMR-WB in TIA-1016 [1]. The bit-exact VMR-WB
\nvalidation includes specific testing of the OEM VMR-WB to the frame
\nerasure processing characteristics of the standard VMR-WB. Should
\nthe candidate VMR-WB differ in any of these components, the codec
\nshall be tested using the objective and subjective tests prescribed
\nby this standard. That is, VMR-WB compliance of a "test codec" can
\nbe achieved by either:<\/p>\n
\u2022 Demonstrating bit-exactness according to the procedure
\ndescribed in Section 3.6, specifically Sections 3.6.5.1 to 3.6.5.4,
\nor<\/p>\n
\u2022 Following the objective and subjective testing procedures set
\nforth in Sections 2.1 and 2.2 of this standard, using processes
\nadditionally defined in Section 3.6, specifically Sections 3.6.5.5
\nto 3.6.5.8.<\/p>\n
With the exception of Section 3.6, the remaining text applies
\nonly to implementations that do not satisfy the requirement for
\nbit-exactness.<\/p>\n
Testing the codec is based on two classes of procedures:
\nobjective tests and subjective tests. In the event that the test
\ncodec fails any of the objective or subjective tests, the test
\ncodec fails the compliance test. Objective tests are based upon
\nactual measurements from the speech codec function. Subjective
\ntests are based on listening tests to judge overall speech quality.
\nThe minimum subjective requirement for the test codec is based upon
\nthe ability of the test codec to demonstrate performance equivalent
\nto or better than that of the VMR-WB floating-point master codec
\nwithin a fixed allowable statistical error.<\/p>\n
The purpose of the testing is not only to ensure adequate
\nperformance between one manufacturer's encoder and decoder but also
\nthat this level of performance is maintained with operation between
\nany pairing of manufacturers' encoders and decoders. This
\ninteroperability is a serious issue. Any variation in implementing
\nthe exact standard must be avoided if it cannot be ensured that
\nminimum performance levels are met when interoperating with all
\nother manufacturers' equipment meeting the standard. This standard
\nprovides a means for measuring performance levels while trying to
\nensure proper interoperation with other manufacturers'
\nequipment.<\/p>\n
The issue of interoperation can only be definitively answered by
\ntesting all combinations of encoder\/decoder pairings. With the
\nnumber of equipment manufacturers expected to supply equipment,
\nthis becomes a prohibitive task; therefore, the objective and
\nsubjective tests rely upon the use of a "master codec". The master
\ncodec is defined as the floating-point implementation of TIA-1016
\n[1] written in the C-programming language. The master codec
\nsoftware, described in Sections 3.4 and 3.5, are used as part of
\nthe interoperability testing. The master codec is available in an
\nassociated Software Distribution as part of TIA-1016 [1].<\/p>\n
By convention in this document, the Courier font is used to
\nindicate C-language and other software constructs, such as file and
\nvariable names.<\/p>\n","protected":false},"excerpt":{"rendered":"
Minimum Performance Specification for the Source-Controlled Variable-Rate Multimode Wideband Speech Codec (VMR-WB) – Service Option 62 for Spread Spectrum Systems<\/b><\/p>\n\n\n
\n Published By<\/td>\n Publication Date<\/td>\n Number of Pages<\/td>\n<\/tr>\n \n TIA<\/b><\/a><\/td>\n 2005<\/td>\n NA<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":0,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2646],"product_tag":[],"class_list":{"0":"post-690306","1":"product","2":"type-product","3":"status-publish","5":"product_cat-tia","7":"first","8":"instock","9":"sold-individually","10":"shipping-taxable","11":"purchasable","12":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/690306","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=690306"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=690306"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=690306"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}